In international COVID-19 developments, China today published promsing findings for the first phase 1 trials results for a COVID-19 vaccine, and the World Health Organization (WHO) released guidance on implementing mass vaccination campaigns in COVID-19 settings.

The global total today rose to 5,169,907 cases, and so far 335,993 people have died from their infections, according to the Johns Hopkins online dashboard.

Three vaccine dosages assessed

Chinese researchers today published the world's first phase 1 trial findings for a COVID-19 vaccine today in The Lancet. Made by CanSino Biologics, the adenovirus type-5 vectored vaccine was tested in 108 healthy adults ages 18 to 60 in Wuhan starting on Mar 16.

The trial excluded people who had been exposed to SARS-CoV-2, the virus that causes COVID-19, and patients stayed in a hotel for 2 weeks after vaccination to avoid exposure to the virus. The participants, split into groups of 36, got one of three dosages intramuscularly and were monitored for 28 days for antibody and T-cell responses, as well as adverse reactions.

The team found that the vaccine was tolerable and immunogenic 28 days after vaccination. Humoral response against SARS-CoV-2 peaked at 28 days, and T-cells were seen starting at 14 days. At least one adverse reaction was seen in the first 7 days for 83% of the low-dose group, 83% of the medium-dose group, and 75% of the high-dose group. Most were mild to moderate, such as injection-site pain, and no serious events were seen 28 days after vaccination.

Though the high-dose vaccine was more immunogenic, participants who received it had more reactions, with severe fever, fatigue, dyspnea, muscle pain, and joint pain reported in some of them, which researchers said might be due to the Ad5 vector, a pattern they saw with an Ebola vaccine using the same vector. Researchers noted that preexisting Ad5 immunity could slow down the rapid immune response to SARS-CoV-2 and lower response peaks, especially for humoral immunity.

They concluded that the vaccine warrants further study. A phase 2 study, with 508 enrolled, is already underway. Researchers said the phase 2 trial is enrolling people older than 60, given that the older age-group is a target for the vaccine.

Groups warn of disruptions in routine immunizations

Meanwhile, childhood vaccines and the disruptions that the COVID-19 pandemic is having on immunization activities took center stage at today's WHO telebriefing, where it, UNICEF, and GAVI, the Vaccine Alliance, called for joint efforts to safely deliver routine immunizations and proceed with vaccination campaigns against sometimes-deadly preventable diseases.

The COVID-19 pandemic has disrupted routine vaccine services in at least 68 countries and could affect about 80 million children under age 1, the groups warned.

Tedros Adhanom Ghebreyesus, PhD, the WHO's director-general, said since the turn of the century, childhood mortality has been halved, mainly due to safe and effective vaccines. "However, we're here today to collectively reinforce the warning that COVID-19 threatens to undermine life-saving immunization services around the world," he said. "This risks putting tens of millions of children in rich and poor countries at risk of killer diseases like diphtheria, measles and pneumonia."

He noted that part of the resolution passed at the World Health Assembly this week was to ensure that countries maintain essential health services. "When health systems are overwhelmed, deaths from outbreaks and from preventable and treatable conditions increase dramatically," he said, adding that Novo Nordisk has donated insulin and glucagon for people with diabetes in low- and middle-income countries, marking the first donation to the WHO of a medicine for a noncommunicable disease.

Early on in the pandemic, the WHO recommended temporarily suspending mass vaccine campaigns, given the risk of virus transmission during the activities, to allow the WHO to find measures to minimize the COVID-19 risk. Today it published new guidance on implementing mass vaccine campaigns during the pandemic.

Brazil cases continue steep rise; Africa tops 100,000 cases

In Brazil, South America's worst hotspot, health officials reported a daily record number of deaths, 1,188, raising its fatality count to 20,027, Al Jazeera reported. Deaths have doubled in the last 11 days, and Brazil now has the sixth highest total in the world.

Sao Paulo state has one-fourth of the country's cases. WHO officials who spoke at today's briefing said Amazonas state in Brazil has a very high attack rate and that like elsewhere in the world, vulnerable groups in Brazil are facing a disproportionate risk.

In other global developments:

Cases in Africa topped 100,000 today, the WHO's African regional office said in a statement. However, it noted that the pattern of COVID-19 spread in Africa has been different than the rest of the world, with cases growing more slowly and without the high mortality that other parts of the world are seeing. Early analysis suggests that the continent's younger population and lower levels of people with underlying conditions may be playing a role. WHO has seen a varied pattern in Africa, but it notes that several nations were quick to order distancing measures.

India today reported its biggest 1-day case rise, with about 6,000 new illnesses reported, according to Reuters. The country is easing some of its lockdown measures, and some domestic flights are set to resume on May 25.

The European Centre for Disease Prevention and Control yesterday launched a new weekly COVID-19 surveillance report. It said trends are decreasing in all but two of the region's countries, with the overall level 68% lower than the Apr 9 peak. Officials estimated that 35% of people with COVID-19 were hospitalized, and of that group, 9% needed respiratory or intensive care unit support and 21% died, though there was variation between countries.

Taliban militants in Afghanistan's Herat province are experiencing COVID-19 illness, the Afghanistan Times reported, based on a video clip. The group's leaders apparently issued a statement to its members to take precautions and to avoid traveling to neighboring countries.